JP5120275B2 - Control device for internal combustion engine - Google Patents

Description

  The present invention relates to a control device for an internal combustion engine, and more particularly, to a control device for an internal combustion engine capable of controlling torque by an intake air amount and ignition timing.

  As disclosed in Japanese Patent Application Laid-Open No. 2008-248836, a technique is known in which torque control is performed using a combination of intake control using a throttle and retard control of ignition timing. When the torque that can be achieved by the intake control is larger than the required torque, the ignition timing is retarded so that the difference is compensated by torque adjustment based on the ignition timing.

JP 2008-248836 A

  The combined use of the intake control and the retard control of the ignition timing can improve the required torque realization accuracy. On the other hand, retarding the ignition timing also leads to a reduction in fuel consumption. As countermeasures against such problems, determine whether to prioritize fuel efficiency or torque accuracy from the vehicle operating conditions. If torque accuracy is prioritized, allow ignition timing retard control and give priority to fuel efficiency. Then, it can be considered as a proposal to prohibit the retard control of the ignition timing.

  However, when the ignition timing retarding control is limitedly used as in the above-mentioned plan, the fuel consumption can be prevented from deteriorating, but the following another problem arises.

  When the retard control of the ignition timing is prohibited, there may be an error between the torque actually realized by the intake control and the required torque. Such torque realization error is caused not only by the accuracy of the calculation model for converting the required torque into the throttle opening, but also by the effect of deposits adhering to the throttle and the influence of environmental conditions such as intake air temperature and atmospheric pressure. sell. However, the above torque realization error is compensated by adjusting the torque by retarding the ignition timing when the ignition timing retarding control is performed. For this reason, at the start of the ignition timing retard control, an unintended torque step corresponding to the torque realization error at that time occurs.

  The present invention has been made to solve the above-described problems, and prevents an unintended torque step from occurring when switching from torque control based on the intake air amount to torque control based on the combined intake air amount and ignition timing. An object of the present invention is to provide a control device for an internal combustion engine that can be used.

In order to achieve the above object, a first invention provides a control device for an internal combustion engine capable of controlling torque by an intake air amount and an ignition timing.
A torque control method selecting means for selecting torque control based on the intake air amount and torque control based on the combined use of the intake air amount and the ignition timing;
An intake control means for receiving an input of a required torque for the internal combustion engine, calculating a target air amount for achieving the input required torque, and controlling an intake air amount based on the target air amount;
When the torque control method is switched from torque control based on the intake air amount to torque control based on the combined use of the intake air amount and the ignition timing, the torque and selection switching achieved by controlling the intake air amount at the time of selection switching Torque realization error calculating means for calculating a torque realization error that occurs between the required torque at the time point ;
If the torque control by the combined use of the intake air quantity and the ignition timing is selected, the correction by adding the torque realization errors in the input required torque, as the target torque for controlling the torque by ignition timing the corrected requested torque Target torque calculation means for calculating,
If the torque control by the intake air quantity and the ignition timing of the combination is selected, the ignition retard control means for retarding the ignition timing in accordance with the deviation between the torque and the target torque to be achieved by controlling the intake air amount ,
It is characterized by having.

According to a second invention, in the first invention,
The target torque calculation means is characterized by gradually changing the target torque to the required torque after the input required torque becomes constant.

In order to achieve the above object, a third aspect of the invention relates to a control device for an internal combustion engine capable of controlling torque by an intake air amount and ignition timing.
A torque control method selecting means for selecting torque control based on the intake air amount and torque control based on the combined use of the intake air amount and the ignition timing;
An intake control means for receiving an input of a required torque for the internal combustion engine, calculating a target air amount for achieving the input required torque, and controlling an intake air amount based on the target air amount;
When the torque control method is switched from torque control based on the intake air amount to torque control based on the combined use of the intake air amount and ignition timing, the required torque at the time of switching the selection is maintained, and this is achieved by controlling the intake air amount. Actuator operation amount correction means for correcting the operation amount of the actuator for intake control so that the torque to be matched with the required torque at the time of switching,
If the torque control by ignition timing together with the intake air amount is selected, on the input required torque, the required torque in the torque and the switching time which is achieved by controlling the intake air amount from being switched selection A target torque calculating means for applying a delay process with a time until the two coincide with each other as a delay time , and calculating a required torque subjected to the delay process as a target torque for torque control based on an ignition timing;
If the torque control by the intake air quantity and the ignition timing of the combination is selected, after the torque to be achieved by controlling the intake air amount matches a required torque in the switching time point, the torque that is achieved by controlling the intake air amount Ignition retard control means for retarding the ignition timing in accordance with a deviation from the target torque;
It is characterized by having.

  According to the first invention, when the torque control based on the combined use of the intake air amount and the ignition timing is selected, a value obtained by adding a torque realization error to the required torque is set as a target torque for torque control based on the ignition timing, Since the ignition timing is retarded so as to achieve the target torque, the actual generated torque shows a relative change with respect to the change in the required torque. As a result, if the required torque changes smoothly before and after switching to torque control using the combined intake air amount and ignition timing, the actual generated torque will also change smoothly, causing an unintended torque step. Is prevented from occurring. In addition, when a step is intentionally added to the required torque before and after the switching, a similar torque step can be generated in the actually generated torque.

  According to the second invention, in addition to the effects of the first invention, it is also possible to make the actually generated torque coincide with the required torque. That is, the torque accuracy can be increased.

  According to the third aspect of the invention, when the torque control based on the combination of the intake air amount and the ignition timing is selected, first, the torque achieved by the control of the intake air amount becomes the required torque at the time of switching the selection. Since the torque is adjusted by retarding the ignition timing after that, if the required torque changes smoothly, the actual generated torque will also change smoothly, causing an unintended torque step. Occurrence is prevented. Further, since the target torque delayed by the required torque is set as the target torque for torque control based on the ignition timing, the actually generated torque can be matched with the required torque according to the third aspect of the invention.

It is the schematic which shows the structure of the control apparatus of the internal combustion engine as Embodiment 1 of this invention. It is explanatory drawing which shows the content of the torque control which concerns on Embodiment 1 of this invention. It is explanatory drawing which shows the comparative example of the torque control which concerns on Embodiment 1 of this invention. It is the schematic which shows the structure of the control apparatus of the internal combustion engine as Embodiment 2 of this invention. It is explanatory drawing which shows the content of the torque control which concerns on Embodiment 2 of this invention. It is the schematic which shows the structure of the control apparatus of the internal combustion engine as Embodiment 3 of this invention. It is explanatory drawing which shows the content of the torque control which concerns on Embodiment 3 of this invention.

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described with reference to FIGS. 1 to 3.

  FIG. 1 is a block diagram showing a configuration of a control device for an internal combustion engine as the first embodiment of the present invention. The control device of the present embodiment is applied to a spark ignition type internal combustion engine (hereinafter simply referred to as an engine), and controls the torque generated by the engine based on the intake air amount and the ignition timing.

  First, control of the intake air amount by the throttle will be described. The intake air amount is controlled based on the required torque. The required torque is supplied to the control device together with the required efficiency from a powertrain manager (not shown) located above the control device. The throttle opening calculation unit 2 of the control device raises the required torque by dividing it by the required efficiency, and calculates the air amount necessary to achieve the required torque after the increase as the target air amount. Here, it is assumed that the required efficiency is set to 1. A map is used to calculate the target air amount. In this map, the torque and the air amount under the optimal ignition timing (MBT or the ignition timing on the retarded side of the trace knock ignition timing) are associated with the operating conditions such as the engine speed as parameters. .

  Next, the throttle opening calculation unit 2 converts the target air amount converted from the required torque into a throttle opening (TA). An inverse model of the intake system air model is used for this conversion process. The air model is a physical model of the intake system, and the response of the air amount to the operation of the throttle is modeled based on fluid dynamics or the like. In the inverse air model, which is the inverse model, operating conditions that affect the relationship between the air amount and the throttle opening, such as valve timing and intake air temperature, can be set as parameters. The throttle opening calculation unit 2 outputs the throttle opening calculated from the target air amount as an opening command value for the throttle.

  Next, the ignition timing control will be described. The ignition timing (SA) that is the operation amount of the ignition device is calculated by the ignition timing calculation unit 4. The ignition timing calculation unit 4 switches the ignition timing control method according to on / off of the ignition use permission flag supplied from the powertrain manager. When the ignition use permission flag is OFF, the ignition timing calculation unit 4 sets the calculated ignition timing as the optimal ignition timing. When the ignition use permission flag is on, the ignition timing is calculated by the method described below. It should be noted that the on / off selection of the ignition use permission flag is performed according to the driving conditions of the vehicle, and the ignition use permission flag is normally off. Then, as described later, when there is a request for torque reduction, the ignition use permission flag is turned on.

  When the ignition use permission flag is on, the ignition timing calculation unit 4 retards the ignition timing according to the difference between the estimated air amount torque and the target torque. The estimated air amount torque means a torque obtained when the ignition timing is set to the optimum ignition timing at the current throttle opening, that is, a torque that can be achieved by the currently estimated intake air amount. Moreover, the target torque here is a target torque for torque control based on the ignition timing, and the calculation is performed by a target torque calculation unit 6 described later. The ignition timing calculation unit 4 calculates the optimal ignition timing as the ignition timing when the estimated air amount torque matches the target torque, and the larger the estimated air amount torque is, the more retarded the ignition timing is with respect to the optimal ignition timing. Increase the amount.

The target torque calculation unit 6 calculates the target torque from the required torque. The following formula is the calculation formula, Tqar is the target torque, and Tqbr is the required torque. Tqe is an estimated air amount torque. n indicates the number of steps after the ignition use permission flag is switched on. Therefore, Tqbr (0) and Tqe (0) indicate the required torque and the estimated air amount torque at the timing when the ignition use permission flag is turned on, that is, at the start timing of torque control using the ignition timing in combination. .
Tqar (n) = Tqbr (n) + (Tqe (0) −Tqbr (0))

  In the above calculation formula, (Tqe (0) −Tqbr (0)) is a torque realization error generated between the torque (estimated air amount torque) achieved by the control of the intake air amount by the throttle and the required torque. . Therefore, according to the above calculation formula, a value obtained by adding a torque realization error to the required torque is calculated as the target torque.

  The content of torque control according to the present embodiment is shown in FIG. This will be described in comparison with the torque movement shown in FIG. FIG. 3 is a diagram showing the torque movement when the required torque is used as it is as the target torque (for torque control by ignition timing) as a comparative example.

  FIG. 2 shows changes in required torque, estimated air amount torque, target torque for torque control according to ignition timing, and actual generated torque. In particular, the target torque is indicated by a broken line, and the actual generated torque is indicated by a thick solid line. FIG. 3 of the comparative example shows changes in required torque, estimated air amount torque, and actual generated torque. 2 and 3, the ignition use permission flag is switched from OFF to ON at time t1, and the required torque is reduced from that time.

  While the ignition use permission flag is off (ignition use prohibition region), only the intake air amount is controlled by the throttle, so that the actual generated torque matches the estimated air amount torque, and the actual generated torque and the required torque There is a torque realization error between them. The movement of torque in the ignition use prohibition region is the same in the case of torque control according to the present embodiment and the case of torque control in the comparative example.

  When the ignition use permission flag is turned on and torque control using the ignition timing is selected, the ignition timing is retarded so as to achieve the required torque in the comparative example shown in FIG. The torque drops sharply to match the required torque, and a torque step corresponding to the torque realization error occurs.

  On the other hand, in the case of the torque control according to the present embodiment shown in FIG. 2, a value obtained by adding a torque realization error to the required torque is set as a target torque for torque control based on the ignition timing. Then, since the ignition timing is retarded so as to realize the target torque, the actual generated torque coincides with the target torque indicated by the broken line and shows a relative change with respect to the change of the required torque. Therefore, as shown in FIG. 2, if the required torque changes smoothly before and after switching to torque control using the ignition timing in combination (before and after time t1), the actual generated torque also changes smoothly. Thus, an unintended torque step is prevented from occurring. Although not shown, when a step difference is intentionally added to the required torque before and after switching, a similar torque step can be generated in the actual generated torque.

  The torque control according to the present embodiment described above is suitable for use when a request for torque reduction is issued from a function in which relative torque change is important (for example, ECT (Electronic Controlled Transmission)). This is because, according to the present embodiment, as can be seen from FIG. 2, the temporal change in the required torque can be reproduced in the actual generated torque.

Embodiment 2. FIG.
Next, a second embodiment of the present invention will be described with reference to FIGS.

  FIG. 4 is a block diagram showing the configuration of the control device for the internal combustion engine as the second embodiment of the present invention. In FIG. 4, elements that are the same as those in the control device of the first embodiment are denoted by the same reference numerals. As can be seen from the difference in reference numerals, the difference between the present embodiment and the first embodiment resides in the target torque calculation unit 8.

Similar to the first embodiment, the target torque calculation unit 8 calculates a target torque for torque control based on the ignition timing from the required torque. For the calculation, the above-described calculation formula is used as in the first embodiment. However, the target torque calculation unit 8 corrects the target torque according to the following equation when the required torque becomes constant after the torque control using the ignition timing is started. In the following equation, K is a coefficient and is set to a value from 0 to -1.
Tqar (n) = Tqar (n−1) + K * (Tqe (0) −Tqbr (0))

  According to the above calculation formula, the target torque Tqar (n) gradually changes toward the required torque Tqbr (n). The target torque calculation unit 8 updates the target torque according to the above calculation formula until the target torque matches the required torque. After the target torque matches the required torque, the target torque calculation unit 8 calculates the required torque as it is as the target torque.

  The content of the torque control according to the present embodiment is shown in FIG. The movement of the torque up to the time point t2 when the required torque becomes constant is the same movement as in the first embodiment. At this time point t2, there is a deviation of the torque realization error between the actually generated torque and the required torque. However, since the correction of the target torque based on the above calculation formula is started from time 2, the actual generated torque gradually approaches the required torque, and eventually the actual generated torque matches the required torque (time t <b> 3). Then, after the target torque coincides with the required torque, the required torque is used as the target torque as it is, so that the actual generated torque changes following the required torque.

  The torque control according to the present embodiment described above is suitable for use when a request for torque reduction is issued from a function in which absolute torque accuracy is important (for example, VSC (Vehicle Stability Control System)). This is because, according to the present embodiment, as can be seen from FIG. 5, the actually generated torque can be matched with the required torque.

Embodiment 3 FIG.
Next, Embodiment 3 of the present invention will be described with reference to FIGS.

  FIG. 6 is a block diagram showing the configuration of the control device for the internal combustion engine as the third embodiment of the present invention. In FIG. 6, elements that are the same as those in the control device of the first embodiment are given the same reference numerals. The control device of the present embodiment is newly provided with a throttle opening correction unit 12 that corrects an opening command value for the throttle. Further, as can be seen from the difference in reference numerals, the contents of the target torque calculator 10 are different between the present embodiment and the first embodiment.

  The throttle opening correction unit 12 functions when the ignition use permission flag is switched from off to on. When the ignition use permission flag is off, the throttle opening correction unit 12 does not function, and the throttle opening calculated by the throttle opening calculation unit 2 is output as it is to the throttle as the opening command value. When the ignition use permission flag is switched on, the throttle opening correction unit 12 holds the required torque at the time of switching. Then, the opening command value for the throttle is corrected so that the estimated air amount torque matches the required torque at the time of switching. Specifically, the air amount error is calculated from the torque realization error at the time of switching, and the correction amount of the throttle opening required to correct the air amount error is determined based on the valve timing and engine speed of the intake valve and the exhaust valve. Calculate with consideration.

  The target torque calculation unit 10 functions in conjunction with the throttle opening correction unit 12. When the ignition use permission flag is switched from OFF to ON, a delay process is applied to the input requested torque, and the required torque after the delay process is calculated as a target torque. The delay time in the delay process is the time from when the ignition use permission flag is switched until the estimated air amount torque matches the required torque at the switching time.

  The present embodiment is also different from the first embodiment in the start timing of the ignition timing retardation by the ignition timing calculation unit 4. In the present embodiment, when the ignition use permission flag is switched from OFF to ON, the ignition timing is not retarded immediately, but the ignition timing is retarded after the delay time has elapsed. The That is, the ignition timing is retarded after the estimated air amount torque matches the target torque.

  The content of torque control according to the present embodiment is shown in FIG. When the ignition use permission flag is turned on and the torque control using the ignition timing is selected, first, the estimated air amount torque is made to coincide with the required torque at the selection switching time t1 by correcting the throttle opening. During this time, since the ignition timing is not retarded, the actual generated torque coincides with the estimated air amount torque and decreases following the decrease in the estimated air amount torque.

  From the time point t2 when the estimated air amount torque matches the required torque, the ignition timing is retarded so as to realize the target torque for torque control based on the ignition timing. Since the target torque is a value obtained by delaying the required torque for the required time from the switching time t1 to the time t2 when the estimated air amount torque matches the required torque, the actual generated torque is smoothly connected before and after the time t2. The occurrence of a torque step that does not occur is prevented. In addition, since the target torque and the required torque match after the delay time has elapsed since the required torque becomes constant, the actual generated torque can finally be made to match the required torque.

  The torque control according to the present embodiment described above is performed when a request for torque reduction is issued from a function that can allow a torque shift in the time direction (for example, shock reduction control before fuel cut or service check control). It is suitable for use.

Others.
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, the control device is configured so that each torque control of the first to third embodiments can be performed, and the torque control to be performed is appropriately selected according to the type of function that issues a torque down request. Also good.

2 Throttle opening calculation unit 4 Ignition timing calculation unit 6, 8, 10 Target torque calculation unit 12 Throttle opening correction unit

Claims (3)

In a control device for an internal combustion engine capable of controlling torque by the amount of intake air and ignition timing,
A torque control method selecting means for selecting torque control based on the intake air amount and torque control based on the combined use of the intake air amount and the ignition timing;
An intake control means for receiving an input of a required torque for the internal combustion engine, calculating a target air amount for achieving the input required torque, and controlling an intake air amount based on the target air amount;
When the torque control method is switched from torque control based on the intake air amount to torque control based on the combined use of the intake air amount and the ignition timing, the torque and selection switching achieved by controlling the intake air amount at the time of selection switching Torque realization error calculating means for calculating a torque realization error that occurs between the required torque at the time point ;
If the torque control by the combined use of the intake air quantity and the ignition timing is selected, the correction by adding the torque realization errors in the input required torque, as the target torque for controlling the torque by ignition timing the corrected requested torque Target torque calculation means for calculating,
If the torque control by the intake air quantity and the ignition timing of the combination is selected, the ignition retard control means for retarding the ignition timing in accordance with the deviation between the torque and the target torque to be achieved by controlling the intake air amount ,
A control device for an internal combustion engine, comprising: 2. The control apparatus for an internal combustion engine according to claim 1, wherein the target torque calculation means gradually changes the target torque to the required torque after the input required torque becomes constant. In a control device for an internal combustion engine capable of controlling torque by the amount of intake air and ignition timing,
A torque control method selecting means for selecting torque control based on the intake air amount and torque control based on the combined use of the intake air amount and the ignition timing;
An intake control means for receiving an input of a required torque for the internal combustion engine, calculating a target air amount for achieving the input required torque, and controlling an intake air amount based on the target air amount;
When the torque control method is switched from torque control based on the intake air amount to torque control based on the combined use of the intake air amount and ignition timing, the required torque at the time of switching the selection is maintained, and this is achieved by controlling the intake air amount. Actuator operation amount correction means for correcting the operation amount of the actuator for intake control so that the torque to be matched with the required torque at the time of switching,
If the torque control by ignition timing together with the intake air amount is selected, on the input required torque, the required torque in the torque and the switching time which is achieved by controlling the intake air amount from being switched selection A target torque calculating means for applying a delay process with a time until the two coincide with each other as a delay time , and calculating a required torque subjected to the delay process as a target torque for torque control based on an ignition timing;
If the torque control by the intake air quantity and the ignition timing of the combination is selected, after the torque to be achieved by controlling the intake air amount matches a required torque in the switching time point, the torque that is achieved by controlling the intake air amount Ignition retard control means for retarding the ignition timing in accordance with a deviation from the target torque;
A control device for an internal combustion engine, comprising:

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